[apalmer]

I think outside of the formal logic space the concept of invariants still are core to programming. Many different strategies such as pure functions, unit tests, type systems, isolation of global state, all key really key around the concept that their are logical truths that always hold for a given program. This is a key way to build large complex programs. it’s impossible to hold every detail of what the code does, so having certain things be known truths goes a long way to enabling one to reason about code.